Usefulness of Rock-Eval pyrolysis, liquid chromatography, and GC/MS in the characterization of Ypresian Chaker organic matter, central-northern Tunisia

The present paper compares Rock-Eval pyrolysis (RE), liquid chromatography (L.C), and gas chromatography-mass spectrometry (GC–MS) data from a geochemical study of Jebel Chaker organic-rich facies, in central-northern Tunisia, in order to obtain independent parameters on organic matter source, composition, and thermal maturity.This study shows a clear evidence of planktonic organic matter as indicated by the hydrogen index, n-alkanes distribution, predominance of saturated, and the high concentration of cholestane. The thermal maturity of Ypresian organic matter was estimated by Tmax, abundance of hetero (N.S.O) compounds, and sterane geochemical parameters such as C29 αα 20S / (20S + 20R) and C29 ββ (ββ + αα) maturity ratios…, to be of low thermal maturity (end of diagenesis–beginning of catagenesis). These data reveal a close concordance between RE, L.C., and GC/MS data, and show that these methods remain valuable and practical for geochemical characterization of sedimentary organic matter.